Still hard to know how large the benefits will really be

Klim McPherson, Professor of public health epidemiology, Cancer and Public Health Unit.

London School of Hygiene and Tropical Medicine, London WC1E 7HT

Papers pp 376, 388

Ever since the implementation of the NHS breast screening programme in 1988 two important questions have been consistently raised. Should the age range of women invited be extended from the current range of 50-64 years, and should the screening interval be reduced from the current three years? If we are to believe the cost effectiveness analysis by Boer et al in this week's issue (p 376),1 an increase in age to 69 and a two year interval would each generate substantial benefits in life years saved and deaths averted—but, needless to say, at a substantial cost. Moreover, the authors'conclusion that extending the age range is expected to prevent more deaths, whereas shortening the screening interval would save more life years leaves policymakers with a—not unfamiliar—ethical dilemma.

It is obviously desirable to improve life expectancy in those women already eligible for screening. Reducing the interval cancer rate, which is particularly high in the third year of …